1. Field of the Invention
The present invention relates to a method of manufacturing an engaging element, e.g. a sprag for a one way clutch.
2. Description of the Prior Art
As illustrated in FIG. 7, a one way clutch has a plurality of engaging elements 71, 71, 71 . . . arranged in a circumferential direction, and is operative to engage such engaging element 71 with both inner and outer rings (not shown) thereby to transmit power from the inner ring to the outer ring or from the outer ring to the inner ring. The configuration of such engaging element 71 is illustrated in FIG. 8. The engaging element 71 has a cam face 71a adapted to be brought into engagement with the outer and inner rings.
Hitherto, engaging elements for a one way clutch of this type have been manufactured in the following way. Initially, a material is drawn to be formed into one having a circumferential surface defining a cam face 71a. Then, a continuous length of the material drawn to have such a circumferential surface is cut by a grinder into parts of a predetermined size, each part being formed with cut surfaces 71b. Next, the parts thus drawn and cut are each barrel-finished for being enabled to have a finished surface. Each of the finished parts is heat treated and then barrel-finished once again.
With the above described prior-art manufacturing method, however, one problem is that during the drawing process the circumferential surface of the material, being a cam face 71a, is likely to have some flaw caused thereto, which necessitates a special control practice intended for avoidance of such naturally results in increased cost.
Another problem is that after the drawing process, some special control is required with respect to the cut size for the drawn material to be cut by a grinder and as well as to the squareness of cut surface 71b relative to the cam face 71a as shown in FIG. 8, which also leads to increased cost.